LED watch MK II

Description:

It is time to give our LED watch from 2012 a through update. We have designed a new main PCB and some of the highlights are:

All the environmental sensors are now included on the main PCB which eliminates the previous add on PCB

Time is now handled by a Maxim DS3231 RTC instead of a Dallas DS1307 RTC

Temperature and pressure are now measured by a Bosch BME280 sensor instead of a Bosch BMP085 sensor

Humidity is now measured by a Bosch BME280 sensor instead of an Aosong AM2302

An AMS CCS811 sensor for measurement of eCO2 level and TVOC level has been added to the main PCB

The PIC18F4620 has been replaced by a PIC18F4685 due to the need of more program memory

We have also made some changes to the design:

A reset jumper has been added to the main PCB

It is no longer possible to connect external buttons to the led watch (menu, enter, up and down)

It is no longer possible to connect an external temperature sensor to the PCB

The control software has therefore also been updated:

A eCO2 level display has been added

A TVOC display has been added

The eCO2 and TVOC measurements are both temperature and humidity compensated based on measurements made by the BME280

An air baseline menu has been added which make it possible to manually save the air baseline for example if the watch has been exposed to fresh air with a low content of CO2 and TVOC and this should be used as a baseline in the future. The air baseline will beside this automatically be saved once a week. The air baseline is used by the sensor when the led watch is powered on in order to be able to show a more accurate eCO2 and TVOC level

An altitude menu has been added where it is possible to enter the current altitude above sea level. The altitude can be between 0 and 2500 meters

A temperature correction menu has been added where it is possible to add between 0 and 9,9 °C/°F to the shown temperature or subtract between 0 and 9,9 °C/°F from the shown temperature

A TX data menu has been added. When TX data is activated all the measurements including different kinds of metadata will be transmitted on port 1 at 38400 baud, 8 data bits, no parity and 1 stop bit

In the remote setup menu the IR remote code for the play/pause button must now also be learned

The firmware menu has been updated so it no longer shows the firmware version and firmware date for the previous add on PCB

The previous "Disp mode" menu has been removed. The led watch has been set to always auto toggle between the displays in the operation menu. This can be paused by pressing the play/pause button on the remote